Lymph nodes are small, bean-shaped glands that serve as filters within the body’s lymphatic system. This system is a network of vessels and organs that plays a central role in the immune system. Lymph nodes contain immune cells that identify and neutralize foreign substances, damaged cells, and cancer cells, preventing them from circulating widely throughout the body. They are strategically located in various regions, including the neck, groin, and armpits.
Understanding Axillary Lymph Nodes
The lymph nodes located in the armpit area are known as axillary lymph nodes. The exact number varies, but individuals typically have between 20 and 49. These nodes are organized into distinct groups based on their anatomical position.
These groups include the anterior (pectoral), posterior (subscapular), lateral (brachial), central, and apical nodes. The anterior nodes are situated along the lower border of the pectoralis minor muscle, while the posterior nodes are found in front of the subscapularis muscle.
Their Role in Body Defense
Axillary lymph nodes are integral to the body’s defense, acting as checkpoints for immune surveillance. They filter lymph fluid that drains from the upper limb, chest wall, and breast. This fluid can carry harmful substances such as bacteria, viruses, and abnormal cells.
Within these nodes, immune cells like lymphocytes and macrophages identify and destroy foreign invaders or damaged cells. This effectively purifies the lymph before it returns to the bloodstream. Their filtration function makes them important sentinels against infection and disease in the upper body regions they drain.
Why They Might Swell
Swollen or tender axillary lymph nodes often signal an active immune response. Common causes include infections affecting the arm, hand, or breast, such as cellulitis or mastitis. Viral illnesses like mononucleosis, measles, or the flu can also cause swelling.
Vaccinations, including for COVID-19, are a frequent cause of temporary swelling. This happens as the immune system activates to produce protective white blood cells in response to the vaccine, a normal reaction. Inflammatory conditions and autoimmune disorders, like rheumatoid arthritis, can also cause lymph nodes to swell.
Significance in Health Monitoring
Axillary lymph nodes are important in health monitoring as indicators of systemic health or localized disease. Healthcare professionals frequently examine these nodes during check-ups, as changes in size, texture, or tenderness can provide clues about underlying conditions. Swelling that is persistent, hard, or painless, especially when unrelated to a clear infection, warrants further investigation.
These nodes are particularly relevant in the context of breast cancer, as they are often the first site where cancer cells spread beyond the breast tissue. Their status helps determine the stage of cancer and guides treatment decisions. Diagnostic procedures like a lymph node biopsy, which involves removing all or part of a node for microscopic examination, can confirm the presence of disease or cancer cells. Awareness of any persistent changes in these nodes and prompt consultation with a healthcare professional are important steps for health management.